1. Field of the Invention
The present disclosure relates to systems and methods for marking a target using thermal radiation, and, in particular, to systems and methods of marking a target with an encoded thermal beam using a target marking system having a light source and a detector that both utilize a common optics assembly.
2. Description of Related Art
In combat arenas, some target marking applications may require use of radiation, such as a thermal beam, to mark targets in a way that may not be detectable by the target. For example, since thermal beams are not visible with the naked eye, a soldier or other user of a thermal target marking system may be able to identify and/or otherwise mark a potential target without the target being able to see, for example, a targeting dot on his person. However, use of thermal radiation to mark targets is not without its own inherent complications.
A quantum cascade laser (“QCL”) may be utilized to emit thermal beams in such applications, however, because the beams emitted by QCLs are inherently divergent, employing a QCL in such applications typically requires additional componentry configured to shape the thermal beam. For example, known beam shaping techniques may be used to increase the resolution of the thermal beam, thereby allowing the beam to appear smaller when impinging upon the target. However, such shaping techniques typically reduce the intensity of the thermal beam. Thus, the resulting beam, although desirably narrower, may be difficult for thermal beam detectors to view at great distances. As a result, such marking systems may be undesirable for use by, for example, snipers or other medium to long-range combat applications.
The viewability/detectability of thermal beams emitted by QCLs may be improved by, for example, gating, phase locking, and/or other known techniques. Such techniques may enable the thermal beam detector to detect the presence of low intensity thermal beams at greater distances. However, utilizing thermal beam detectors configured for gating or phase locking, in conjunction with a QCL, may be difficult and cumbersome in combat arenas. For example, relatively large optical components may be required optically downstream of the QCL to facilitate the required shaping of the thermal beam. In addition, the thermal beam detector typically employs a second set of relatively large optical components to facilitate the requisite gating, phase locking, or other conditioning of the detected beam. Together, such components may be prohibitively large and heavy to be mounted to, for example, a typical firearm. In addition, such components may require, among other things, one or more electrical connections enabling communication between, for example, the QCL and the thermal beam detector components. Such connections are often facilitated by one or more wires extending between the QCL and the detector. Such wires can easily be disconnected or become caught on obstructions during use, further reducing the useability of such systems in combat arenas.
Thus, the need exists for a relatively light-weight, compact target marking system configured to emit a relatively narrow marking beam over long distances and to detect resulting radiation emitted by the impinged target.